Commit 9be34be8 authored by Mark Brown's avatar Mark Brown Committed by Catalin Marinas
Browse files

arm64: Add macro version of the BTI instruction 



BTI is only available from v8.5 so we need to encode it using HINT in
generic code and for older toolchains. Add an assembler macro based on
one written by Mark Rutland which lets us use the mnemonic and update
the existing users.

Suggested-by: default avatarMark Rutland <mark.rutland@arm.com>
Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20211214152714.2380849-2-broonie@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 580b536b

arch/arm64/crypto/aes-modes.S

+5 −5
Original line number Diff line number Diff line
@@ -363,15 +363,15 @@ ST5( mov v4.16b, vctr.16b ) 
	adr		x16, 1f

	sub		x16, x16, x12, lsl #3

	br		x16

	hint		34			// bti c

	bti		c

	mov		v0.d[0], vctr.d[0]

	hint		34			// bti c

	bti		c

	mov		v1.d[0], vctr.d[0]

	hint		34			// bti c

	bti		c

	mov		v2.d[0], vctr.d[0]

	hint		34			// bti c

	bti		c

	mov		v3.d[0], vctr.d[0]

ST5(	hint		34				)

ST5(	bti		c				)

ST5(	mov		v4.d[0], vctr.d[0]		)

1:	b		2f

	.previous

arch/arm64/include/asm/assembler.h

+10 −0
Original line number Diff line number Diff line
@@ -790,6 +790,16 @@ alternative_endif 
.Lnoyield_\@:

	.endm



/*

 * Branch Target Identifier (BTI)

 */

	.macro  bti, targets

	.equ	.L__bti_targets_c, 34

	.equ	.L__bti_targets_j, 36

	.equ	.L__bti_targets_jc,38

	hint	#.L__bti_targets_\targets

	.endm



/*

 * This macro emits a program property note section identifying

 * architecture features which require special handling, mainly for

arch/arm64/include/asm/linkage.h

+1 −6
Original line number Diff line number Diff line
@@ -6,12 +6,7 @@ 


#if defined(CONFIG_ARM64_BTI_KERNEL) && defined(__aarch64__)



/*

 * Since current versions of gas reject the BTI instruction unless we

 * set the architecture version to v8.5 we use the hint instruction

 * instead.

 */

#define BTI_C hint 34 ;

#define BTI_C bti c ;



/*

 * When using in-kernel BTI we need to ensure that PCS-conformant assembly